Generally, there are two types of lawn mowers: rotary lawn mowers in which a single blade rotates about an axis perpendicular to the ground, and reel-type lawn mowers that have a series of blades mounted on a reel that rotates about an axis parallel to the ground. This invention is particularly concerned with a mulching device for use on a powered, as opposed to a manual, reel-type lawn mower.
With increasing regulation of landfills and a shortage of sites due to urban expansion, there is an increasing demand to avoid or minimize the use of landfills for grass cuttings from domestic gardens, parks, golf courses and the like. Indeed, some landfills now prohibit the deposit of such lawn cuttings. Thus, with environmental awareness increasing and as landfill space decreasing, the need for practical and cost-effective alternatives for the disposal of grass cuttings is growing.
Further, lawn fertilizers are expensive and many contain active chemicals that are not environmentally sound. It is well known that finely cut mulch can have beneficial horticultural properties when utilized as a fertilizer. The beneficial horticultural properties of a fine mulch include reducing evaporation, maintaining constant soil temperature, preventing erosion, controlling weeds, and enriching the soil. There is therefore a need for a simple, effective and inexpensive mulcher of cut grass that will recycle grass cuttings as a fertilizer for lawns and parks. This need is met with the present invention, the use of which may greatly reduce or eliminate the need for a fertilizer on a lawn.
Furthermore, in arid states, particularly those such as California where water is often in short supply, an efficient grass mulcher may provide additional benefits. Where the grass is sufficiently, finely and properly mulched, the mulch collects around the base of the grass and not only nourishes it, but also reduces water evaporation from the grass and the soil around its roots, so that less water may be required to maintain the grass. There is therefore a need for a simple and effective device that will properly and finely mulch grass cuttings to increase water retention in the lawn. The present invention also achieves these objectives.
Furthermore, in addition to the environmental and horticultural advantages already discussed, the mulching device of the present invention also increases the aesthetics of the lawn. In conventional mowing, cut grass is often dropped on the lawn, either because the grass catcher is left off or it leaks during use. This produces unsightly streaks and rows of cut grass extending across the lawn. These rows of cut grass, if not raked or vacuumed, will later dry out and spoil the appearance of a lawn. Use of the device of this invention while mowing the lawn eliminates this problem. Thus, the lawn may be kept smooth and aesthetically pleasing.
Mulching devices for manual reel-type lawn mowers are known. For example, U.S. Pat. No. 2,517,184 to Elliott, et al. discloses a hood which is mounted over the cutting reel and which has spiral-shaped ribs located on its underside for directing cut grass back into the cutting reel to be recut for mulching. However, Elliott is concerned only with manual, non-powered lawn mowers. The spiral-shaped design in Elliott is also of little or no practical utility in powered mowers, because the increased volume and speed of grass cuttings in such mowers would clog such a design in a power mower, especially if the grass was wet. Moreover, in Elliott, the ribs are perpendicular with respect to the hood for the mower. The applicant has found that such ribs decrease the velocity of cut grass too much in a power mower. Thus, in a power mower the discharged grass impinges on such ribs at a high angle and loses a substantial amount of velocity. This adversely affects performance of the mower.
The hood arrangement in Elliott also is unsuitable for use in a power mower because the space between the blades and hood would be too great in a power mower and would therefore tend to build up grass in that space and clog the machine. Power mowers require a hood or shield that is quite close to the blades, so that cut grass is brought up and over the top of the reel with enough force to prevent clogging.
In any event, manually operated reel-type lawn mowers, such as shown in Elliott, are disfavored nowadays. Power reel-type lawn mowers are much preferred for their speed and efficiency, especially by commercial gardeners. There is therefore a need for practical mulching devices for power reel-type lawn mowers. That is satisfied by the present invention.
Some commercial power reel mowers on the market today have a rib like structure in the passageway between the reel and the shield or hood behind the reel. Certain mowers made in the United States by King-O-Lawn in the 1950's and 1960's and by McLane in the 1970's have a series of ribs in the outlet to that passageway that are perpendicular to the surface to which they are attached and which are for directing the cut grass upwardly and forwardly into a grass catcher attached to the mower. Thus such mowers perform no mulching function.
Accordingly, the above objectives are met by the mulching device of the present invention, which is designed to be mounted on conventional powered reel-type mower machines so as to direct the flow of cut grass into the blades for more complete comminution, so as to reduce the bulk of the clippings and thus distribute them upon the turf as a mulch having beneficial horticultural properties.